1. Field of the Invention
The present invention relates to an endoscope provided with a light emitting device, as an illuminating section, at a distal end portion of an insertion portion.
2. Description of the Related Art
Endoscopes are widely used in medical fields and industrial fields. Targets to be diagnosed or observed through endoscopes are inside a living body or a plant. Therefore, a light source for illuminating a target to be observed is required when endoscopic observation is performed.
A common endoscope apparatus is provided with an endoscope, and a light source device as an external device of the endoscope. Illumination light emitted by the light source device is transmitted through a light guide inserted in the endoscope. The transmitted illumination light is emitted toward a target to be observed from an illumination window arranged at a distal end of an insertion portion.
In recent years, an endoscope has been proposed, which is provided with a light emitting device such as a light-emitting diode (LED) at a distal end portion of an insertion portion, instead of a combination of a light source device and a light guide fiber, and which directly illuminates a target to be observed with the light emitted by the light emitting device. As shown in FIG. 1, in addition to an LED light source unit 4 configuring an illuminating section, internal components such as an observation unit 5 and various fluid tubes 6 are attached to a distal end rigid member 3 configuring a distal end portion 2 of an endoscope 1. The LED light source unit 4 is configured by including an LED ceramic substrate 8 on which an LED light source 41 is mounted. In the endoscope 1, the size or the like of the LED ceramic substrate 8 configuring the LED light source unit 4 is limited.
In order to avoid interference between the LED ceramic substrate 8 and the observation unit 5, or interference between the LED ceramic substrate 8 and internal components, an escape portion 8a such as a step or a cutout is formed on the LED ceramic substrate 8.
In an LED unit assembling work as shown in FIG. 2, the LED light source unit 4 is assembled to an illumination disposing portion 11 as a recessed portion of a lens cover 10 fixed to the distal end rigid member 3. In an observation unit assembling work, the observation unit 5 is assembled to the distal end rigid member 3, as shown in FIG. 3.